From 26432799c902b76e87f68f5c88f2146a78ba84af Mon Sep 17 00:00:00 2001 From: Stefan Behrens Date: Thu, 15 Aug 2013 17:11:22 +0200 Subject: Btrfs: introduce uuid-tree-gen field In order to be able to detect the case that a filesystem is mounted with an old kernel, add a uuid-tree-gen field like the free space cache is doing it. It is part of the super block and written with each commit. Old kernels do not know this field and don't update it. Signed-off-by: Stefan Behrens Signed-off-by: Josef Bacik Signed-off-by: Chris Mason --- fs/btrfs/ctree.h | 5 ++++- fs/btrfs/transaction.c | 1 + 2 files changed, 5 insertions(+), 1 deletion(-) (limited to 'fs/btrfs') diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index df2b9c22b4cf..02b1cefbc308 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -482,9 +482,10 @@ struct btrfs_super_block { char label[BTRFS_LABEL_SIZE]; __le64 cache_generation; + __le64 uuid_tree_generation; /* future expansion */ - __le64 reserved[31]; + __le64 reserved[30]; u8 sys_chunk_array[BTRFS_SYSTEM_CHUNK_ARRAY_SIZE]; struct btrfs_root_backup super_roots[BTRFS_NUM_BACKUP_ROOTS]; } __attribute__ ((__packed__)); @@ -2900,6 +2901,8 @@ BTRFS_SETGET_STACK_FUNCS(super_csum_type, struct btrfs_super_block, BTRFS_SETGET_STACK_FUNCS(super_cache_generation, struct btrfs_super_block, cache_generation, 64); BTRFS_SETGET_STACK_FUNCS(super_magic, struct btrfs_super_block, magic, 64); +BTRFS_SETGET_STACK_FUNCS(super_uuid_tree_generation, struct btrfs_super_block, + uuid_tree_generation, 64); static inline int btrfs_super_csum_size(struct btrfs_super_block *s) { diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c index 72ab0dd31937..e76237c8802a 100644 --- a/fs/btrfs/transaction.c +++ b/fs/btrfs/transaction.c @@ -1380,6 +1380,7 @@ static void update_super_roots(struct btrfs_root *root) super->root_level = root_item->level; if (btrfs_test_opt(root, SPACE_CACHE)) super->cache_generation = root_item->generation; + super->uuid_tree_generation = root_item->generation; } int btrfs_transaction_in_commit(struct btrfs_fs_info *info) -- cgit v1.2.3